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Many modern big data applications feature large scale in both numbers of responses and predictors. Better statistical efficiency and scientific insights can be enabled by understanding the large-scale response-predictor association network structures via layers of sparse latent factors ranked by importance. Yet sparsity and orthogonality have been two largely incompatible goals. To accommodate both features, in this paper, we suggest the method of sparse orthogonal factor regression (SOFAR) via the sparse singular value decomposition with orthogonality constrained optimization to learn the underlying association networks, with broad applications to both unsupervised and supervised learning tasks, such as biclustering with sparse singular value decomposition, sparse principal component analysis, sparse factor analysis, and spare vector autoregression analysis. Exploiting the framework of convexity-assisted nonconvex optimization, we derive nonasymptotic error bounds for the suggested procedure characterizing the theoretical advantages. The statistical guarantees are powered by an efficient SOFAR algorithm with convergence property. Both computational and theoretical advantages of our procedure are demonstrated with several simulations and real data examples. 

We report a measurement of the $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{\pi }^0$cross section in the energy range from 0.62 to 3.50 GeV using an initial-state radiation technique. We use an $e^{+}{e}^{-}$data sample corresponding to $191{\mathrm{fb}}^{-1}$of integrated luminosity, collected at a center-of-mass energy at or near the $\mathrm{\Upsilon }\left(4S\right)$resonance with the Belle II detector at the SuperKEKB collider. Signal yields are extracted by fitting the two-photon mass distribution in $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{\pi }^0\gamma$events, which involve a ${\pi }^0\to \gamma \gamma$decay and an energetic photon radiated from the initial state. Signal efficiency corrections with an accuracy of 1.6% are obtained from several control data samples. The uncertainty on the cross section at the $\omega$and $\varphi$resonances is dominated by the systematic uncertainty of 2.2%. The resulting cross sections in the 0.62–1.80 GeV energy range yield $a_{\mu }^{3\pi }=[48.91\pm 0.23(\mathrm{stat})\pm 1.07(\mathrm{syst}\left)\right]\times {10}^{-10}$for the leading-order hadronic vacuum polarization contribution to the muon anomalous magnetic moment. This result differs by 2.5 standard deviations from the most precise current determination. Published by the American Physical Society2024 

We report measurements of time-dependent $CP$asymmetries in $B^0\to K_S^0{\pi }^0\gamma$decays based on a data sample of $(388\pm 6)\times {10}^{6}B\overline{B}$events collected at the $\mathrm{\Upsilon }\left(4S\right)$resonance with the Belle II detector. The Belle II experiment operates at the SuperKEKB asymmetric-energy $e^{+}{e}^{-}$collider. We measure decay-time distributions to determine $CP$-violating parameters $S$and $C$. We determine these parameters for two ranges of $K_S^0{\pi }^0$invariant mass: $m\left(K_S^0{\pi }^0\right)\in (0.8,1.0)\mathrm{GeV}/c^2$, which is dominated by $B^0\to K^{*0}(\to K_S^0{\pi }^0)\gamma$decays, and a complementary region $m\left(K_S^0{\pi }^0\right)\in (0.6,0.8)\cup (1.0,1.8)\mathrm{GeV}/c^2$. Our results have improved precision as compared to previous measurements and are consistent with theory predictions. Published by the American Physical Society2025 

We describe a measurement of charge-parity ( $CP$) violation asymmetries in $B^0\to {\eta }^{\prime }{K}_{\mathrm{S}}^0$decays using Belle II data. We consider ${\eta }^{\prime }\to \eta (\to \gamma \gamma ){\pi }^{+}{\pi }^{-}$and ${\eta }^{\prime }\to \rho (\to {\pi }^{+}{\pi }^{-})\gamma$decays. The data were collected at the SuperKEKB asymmetric-energy $e^{+}{e}^{-}$collider between the years 2019 and 2022, and contain $(387\pm 6)\times {10}^6$bottom-antibottom meson pairs. We reconstruct $829\pm 35$signal decays and extract the $CP$violating parameters from a fit to the distribution of the proper-decay-time difference between the two $B$mesons. The measured direct and mixing-induced $CP$asymmetries are $C_{{\eta }^{\prime }{K}_{\mathrm{S}}^0}=-0.19\pm 0.08\pm 0.03$and $S_{{\eta }^{\prime }{K}_{\mathrm{S}}^0}=+0.67\pm 0.10\pm 0.03$, respectively, where the first uncertainties are statistical and the second are systematic. These results are in agreement with current world averages and standard model predictions. Published by the American Physical Society2024 

A<sc>bstract</sc> We report a determination of the CKM angleϕ₃, also known asγ, from a combination of measurements using samples of up to 711 fb⁻¹from the Belle experiment and up to 362 fb⁻¹from the Belle II experiment. We combine results from analyses ofB⁺→ DK⁺,B⁺→ Dπ⁺, andB⁺→ D^*K⁺decays, whereDis an admixture ofD⁰and$$ {\overline{D}}^0 $$ ${\overline{D}}^0$mesons, in a likelihood fit to obtainϕ₃= (75.2±7.6)^°. We also briefly discuss the interpretation of this result. 

The ratio of branching fractions $R\left(D^{*}\right)=\mathcal{B}(\overline{B}\to D^{*}{\tau }^{-}{\overline{\nu }}_{\tau })/\mathcal{B}(\overline{B}\to D^{*}{\ell }^{-}{\overline{\nu }}_{\ell })$, where $\ell$is an electron or muon, is measured using a Belle II data sample with an integrated luminosity of $189{\mathrm{fb}}^{-1}$at the SuperKEKB asymmetric-energy $e^{+}{e}^{-}$collider. Data is collected at the $\mathrm{\Upsilon }\left(4\mathrm{S}\right)$resonance, and one $B$meson in the $\mathrm{\Upsilon }\left(4\mathrm{S}\right)\to B\overline{B}$decay is fully reconstructed in hadronic decay modes. The accompanying signal $B$meson is reconstructed as $\overline{B}\to D^{*}{\tau }^{-}{\overline{\nu }}_{\tau }$using leptonic $\tau$decays. The normalization decay, $\overline{B}\to D^{*}{\ell }^{-}{\overline{\nu }}_{\ell }$, produces the same observable final-state particles. The ratio of branching fractions is extracted in a simultaneous fit to two signal-discriminating variables in both channels and yields $R\left(D^{*}\right)={0.262}_{-0.039}^{+0.041}\left(\mathrm{stat}{)}_{-0.032}^{+0.035}\right(\mathrm{syst})$. This result is consistent with the current world average and with Standard Model predictions. Published by the American Physical Society2024 

A<sc>bstract</sc> We report measurements of thee⁺e⁻→$$ B\overline{B} $$ $B\overline{B}$,$$ B{\overline{B}}^{\ast } $$ $B{\overline{B}}^{\ast }$, and$$ {B}^{\ast }{\overline{B}}^{\ast } $$ $B^{\ast }{\overline{B}}^{\ast }$cross sections at four energies, 10653, 10701, 10746 and 10805 MeV, using data collected by the Belle II experiment. We reconstruct oneBmeson in a large number of hadronic final states and use its momentum to identify the production process. In the first 2 – 5 MeV above$$ {B}^{\ast }{\overline{B}}^{\ast } $$ $B^{\ast }{\overline{B}}^{\ast }$threshold, thee⁺e⁻→$$ {B}^{\ast }{\overline{B}}^{\ast } $$ $B^{\ast }{\overline{B}}^{\ast }$cross section increases rapidly. This may indicate the presence of a pole close to the threshold. 

This paper presents a search for massive, charged, long-lived particles with the ATLAS detector at the Large Hadron Collider using an integrated luminosity of $$140~fb^{−1}$$ of proton-proton collisions at $$\sqrt{s}=13$$~TeV. These particles are expected to move significantly slower than the speed of light. In this paper, two signal regions provide complementary sensitivity. In one region, events are selected with at least one charged-particle track with high transverse momentum, large specific ionisation measured in the pixel detector, and time of flight to the hadronic calorimeter inconsistent with the speed of light. In the other region, events are selected with at least two tracks of opposite charge which both have a high transverse momentum and an anomalously large specific ionisation. The search is sensitive to particles with lifetimes greater than about 3 ns with masses ranging from 200 GeV to 3 TeV. The results are interpreted to set constraints on the supersymmetric pair production of long-lived R-hadrons, charginos and staus, with mass limits extending beyond those from previous searches in broad ranges of lifetime 

We present GFlaT, a new algorithm that uses a graph-neural-network to determine the flavor of neutral $B$mesons produced in $\mathrm{\Upsilon }\left(4S\right)$decays. It improves previous algorithms by using the information from all charged final-state particles and the relations between them. We evaluate its performance using $B$decays to flavor-specific hadronic final states reconstructed in a $362{\mathrm{fb}}^{-1}$sample of electron-positron collisions collected at the $\mathrm{\Upsilon }\left(4S\right)$resonance with the Belle II detector at the SuperKEKB collider. We achieve an effective tagging efficiency of $(37.40\pm 0.43\pm 0.36\%)$, where the first uncertainty is statistical and the second systematic, which is 18% better than the previous Belle II algorithm. Demonstrating the algorithm, we use $B^0\to J/\psi K_{\mathrm{S}}^0$decays to measure the mixing-induced and direct $CP$violation parameters, $S=(0.724\pm 0.035\pm 0.009)$and $C=(-0.035\pm 0.026\pm 0.029)$. Published by the American Physical Society2024 

We measure the tau-to-light-lepton ratio of inclusive $B$-meson branching fractions $R\left(X_{\tau /\ell }\right)\equiv \mathcal{B}(B\to X\tau \nu )/\mathcal{B}(B\to X\ell \nu )$, where $\ell$indicates an electron or muon, and thereby test the universality of charged-current weak interactions. We select events that have one fully reconstructed $B$meson and a charged lepton candidate from $189{\mathrm{fb}}^{-1}$of electron-positron collision data collected with the Belle II detector. We find $R\left(X_{\tau /\ell }\right)=0.228\pm 0.016\left(\mathrm{stat}\right)\pm 0.036\left(\mathrm{syst}\right)$, in agreement with standard-model expectations. This is the first direct measurement of $R\left(X_{\tau /\ell }\right)$. Published by the American Physical Society2024